DE1158365B - Gelatin-silver halide photographic emulsions, emulsion layers and materials - Google Patents

Description

The invention relates to improved photographic silver halide emulsions, emulsion layers and films coated with these emulsions.

Photographic films intended for use in graphics should be so dimensionally stable that: if several films are placed on top of one another, as is usual for color reproduction, these films are used for Take cover, d. H. are in exact spatial correspondence. To a high level To achieve dimensional stability, the photographic emulsions are often applied to glass plates. More recently, hydrophobic base films have been used, ζ. B. those made of polyethylene terephthalate, used in place of glass for these purposes; however, this eliminates the shortcomings of the Emulsions not eliminated.

An undesirable property of currently available graphic films is the change in the optical density of the image when transitioning from the wet to the dry state. In the In practice, it is common practice to develop the film to the required optical density that passes through Visually or in a densitometer while the film is still wet. Then the Development interrupted. This is not an accurate method because the optical density changes as it dries of the film changes, and therefore it is often necessary to go through a number of development processes to get a single negative with the correct optical density. aside from that the amount of density change upon drying varies with the drying conditions. The previous Procedures were costly and time consuming.

Attempts have already been made to replace the gelatin with synthetic ones To replace binders in order to improve their properties for use in graphics; but this was in view of the unique photographic and colloid chemistry The properties of gelatin as a binder are only partially accompanied by success. Improvements in one Respects usually come at the expense of another and more important quality.

So describes z. B. Ewa in the »Journal for Scientific Photographic, Photophysics and Photochemie ", 52. 1957," pp. 1 to 24. Silver halide emulsions using dextran, a polyglucose bound in a] -6 bond. The usage however, using dextran as the sole binder for silver halide grains has several disadvantages. It is Z. B. difficult or impossible to produce an emulsion that contains dextran as the only colloid binder in the all- Photographic

Gelatin silver halide emulsions,
Emulsion layers and materials

Applicant:

EI du Pont de Nemours and Company,
Wilmington, Del. (V. St. A.)

Representative: Dr.-Ing. W. Abitz, patent attorney,
Munich 27, Pienzenauer Str. 28

Claimed priority:
V. St. v. America of February 27, 1962 (No. 176 140)

Abraham Bernard Cohen, Springfield,
and Comer Drake Shacklett, Roselle, NJ

(V. St. A.),
have been named as inventors

common customary way of solidifying by cooling. Another disadvantage of dextran is that it is bad Protective colloid effect for silver halide grains. Many other binder modifications are suggested been; however, none of them provide the right balance between the main ones physical and photographic properties required for graphic films. The invention provides a unique silver halide photographic emulsion and emulsion layer is available that retains the advantages of gelatin, but eliminates certain disadvantages will. Another purpose of the invention is to provide photographic emulsion layers and films for graphic art, which have improved solidity and which the optical density of the developed image when transitioning from wet to dry remains stable. Another object of the invention is the production of emulsion layers and photographic ones Elements that can be dried faster.

309 750/322

The improved gelatin-silver halide emulsions according to the invention contain, in addition to the silver halide grains

1. an aqueous phase, which as constituents

a) 20 to 85 parts by weight of gelatin and

b) 2.5 to 40 parts by weight of a water-soluble polysaccharide of the empirical formula

(C ₆ H ₁₀ O.) ,, or (C ₅ H ₈ O ₄ ) ,,

contains, in which the monomer units are naturally occurring aldoses or ketoses, which are linked by glycoside bonds, and in which η has a value of 20 to 600, and

2. 10 to 70 parts by weight of a non-aqueous phase of water dispersible dispersed therein colloidal particles (preferably from

Vinyl addition polymer of an ethylenically unsaturated Monomers with a molecular weight of less than 250.

However, the texture, anti-robbery and practical photographic handleability are remarkable improved. For example, the coefficient of moisture expansion and the change in size are at Processing of the photosensitive silver halide into a silver image is significantly reduced. The optical one Density of the image in transition from wet to dry state is remarkable stabilized so that the final optical density in

ίο dry condition from the measurement of the optical Density when wet can be accurately predicted.

Furthermore, the drying rate of the treated, exposed film is higher, the tendency to become Rolling up at low moisture levels is reduced and the impact resistance and the bond strength to the substrate are significantly improved. These Combination of properties and results is

• 1 τ-. i__i · ι surprising and of particular technical concern

emem nuttleren diameter of less than _{20 German f & photographic films which for} ^ _Gra _

400 πΐμ) from a practically water-insoluble _{pMk be} ⁵ _stimi £ _{t sin} J ^ _{1 with these FUmen often thick}

Emulsion layers can be used for the reproduction of continuous tones.

According to a preferred embodiment of the

In addition, the emulsion can contain even lower amounts of gelatin-silver halide, usually less than 5 weight percent of a cationic optical sensitizing dye three binders, on different emulsifiers and a dispersion of the water-insoluble vinyl auxiliaries, Dispersants, coating auxiliary polymers are added, which are incorporated therein with the help agents, etc. included. an amphoteric dispersant, preferably one

The new 30 amphoteric alkyliminomonocarboxylates containing the three components of the formula colloidal binders - silver halide emulsions
can be made in a number of ways.
In a practical embodiment of the invention, photosensitive silver halide or a
Mixture of such halides in an aqueous photo 35 ρ has the value 2 - m and M is a hydrogen, Nagraphischen gelatin solution precipitated. The obtained trium, potassium or ammonium ion means. In emulsion or dispersion, the protective colloid retains
and other properties of photographic grade gelatin. To the precipitated silver halide emulsion which are washed, ripened 40
can, etc., be suitable sensitizers and
optionally other emulsion auxiliaries added,
and the emulsion is digested. To the digested
Emulsion are separately or simultaneously one

aqueous solution or dispersion of the polysaccharide 45 of N-dodecyl - ^ - iminodipropionate. At the first of the dispersant called water-insoluble vinyl addition polymer, "tallow" means an addition. After a thorough mixing mix of hydrocarbon residues, namely oleyl, has taken place, the three components palmityl, stearyl and myristyl residues in the series containing colloidal silver halide dispersion due to decreasing concentration. You can't one Carrier, e.g. B. a hydrophobic carrier film, 50 ionic or cationic surfactants

RNH _m (CH ₂ CH ₂ COOM) ,,

is dispersed, in which R is an alkyl group having 12 to 18 carbon atoms, m is 0 or 1,

generally, the dispersant is used in amounts of from 0.5 to 15.0 percent by weight of the water-insoluble Vinyl polymers applied.

Suitable amino acid dispersants are described in U.S. Pat. No. 2,816,920 and im Commercially available. Two of these dispersants that are of particular interest are disodium N "tallow" / hminopropionate and the disodium salt

applied and dried. Further gelatin can be added together with the other two colloids so that the finished silver halide emulsion or dispersion has the required amount of gelatin contains.

After drying, the photosensitive silver halide layer is sensitometrically through a neutral density wedge exposed, processed by developing, fixing, etc., and the image densities are use; however, the best results, especially in the case of panchromatic silver halide emulsions, with the aid of the amphoteric alkyliminodicarboxylate described above as a dispersant achieved.

The polysaccharides used according to the invention can be used as water-soluble polycondensates of monosaccharides are characterized by the splitting off of water with the formation of glycoside

read on a desitometer of a known type. The 60 ties are linked together. For this ge

new silver halide emulsion containing the gelatin, the polysaccharide and the water-insoluble vinyl polymer provides a clear film which, like a pure gelatin film, is suitable for aqueous development and Fixing baths is permeable and as a result of the similarity Photosensitometric similar in the grain structure and in the core size distribution of the silver halide Has properties. Its physical listen to both pentose and hexose derivatives the following empirical equations:

η C ₆ H ₁₂ O ₆

(C ₆ H ₁₀ O ₅ ) "+ (W (C ₅ H ₈ O ₄ )" + (HI) H ₂ O

While with the naturally occurring polysaccharides the number η from ten to several

"C ₅ H ₁₀ O ₅

can vary by a thousand, the polysaccharides preferred according to the invention have twenty to six hundred such units or molecular weights in the range of 2,500 to 100,000. Polysaccharides having molecular weights below the lowest value of this range diffuse into water so easily that they are washed out of the films in the photographic processing process, while polysaccharides with molecular weights of more than 100,000 have insufficient water solubility, are incompatible with gelatin or result in solutions of too high a viscosity. The viscosities of 5% aqueous solutions should preferably be at 25 ° C be below 100 cP.

Most of the polysaccharides used according to the invention can also use the generic name "Glycans," and most of these are known by generic names where the ending "-öse" of the base sugar is replaced by the ending "-an", z. B. glucan or dextran, Galactan, mannan, etc .; however, in some cases the common names are used, such as B. inulin.

The polysaccharides used according to the invention can be linear or branched-chain homo- or Heteroglycans according to the classification system in Table V on p. 22 to 26 of the work »Polysaccharides Chemistry ”by R. L. Whistler and C.L. Smart (Academic Press, New York, 1953). Each repeating unit in the above empirical formulas can be viewed as a derivative of a naturally occurring hexose or pentose, such as

CHO

CHOH

CHOH

CHOH

CHOH

CH ₀ OH

CHO

CHOH

CH ₀ OH

C = O

CHOH CHOH

or I
CHOH CHOH

f
CH ₀ OH

CHOH

CH ₂ OH

being one of the hydroxyl groups with the carbonyl group of the same molecule through hemiacetal formation and the formation of a glycoside (acetal) bond reacts with a second hemiacetal to form a pyranose or furanose ring. With Ketoses form the corresponding ketals.

The exact point of attachment of the glycoside bond (1,4 ', 1,6', etc.) and orientation (α or β) is not always known, but neither does it appear to be important provided that the polysaccharide is water soluble. Certain water-insoluble polysaccharides with 1.4 - /? - bonds, such as xylan and cellulose, are excluded from the use according to the invention; however, galactan, which has a similar bond but is water-soluble, is one of the compounds which can be used according to the invention in view of the restriction to water-soluble glycans. Inulin, which is a fructan of low water solubility and high viscosity, shows the beneficial effects according to the invention to a lesser extent than the more soluble polysaccharides. In addition to the sugar residues, these polysaccharides can also contain up to 15 percent by weight of other naturally occurring protein or carbohydrate residues, provided that these residues do not impair the solubility or viscosity of the compounds.

The polyhexoses which can be used according to the invention include the water-soluble mannans, galactans, Fructans (including the levans), glucofructans, galactomannans, laminarins, and dextrans Dextrins etc. as well as hydrolyzed ^, water-soluble ίο derivatives of cellulose, starch and glycogen. the Dextrans, which are industrially produced by bacterial fermentation of sucrose, are one according to the invention particularly preferred class of polysaccharides. Preferred dextrins and dextrans are in Belgian patents 584132 and 592477. Polysaccharides which can be used according to the invention, which contain pentoses are araban and arabogalactans.

In the choice of the colloidal dispersion of the water-insoluble vinyl polymers, which also include copolymers there is a considerable range of variation. A preferred class are Acrylic and methacrylic acid alkyl esters, e.g. B. Polymers and copolymers of methyl acrylate, -äthyl-, -butyl- and ethylhexyl ester or methacrylic acid methyl and butyl ester. Also acrylic acid or methacrylic acid itself can be used to produce valuable copolymers. However, together with most of the mixed monomers, no more than 10 mole percent becomes one such acid is used in the polymerization so that the copolymer remains insoluble in water. Others which can be used for the preparation of dispersions of water-insoluble polymers and copolymers Classes of vinyl monomers are the vinyl esters, such as the acetate, propionate, etc., vinyl and vinylidene halides, such as vinylidene chloride, styrene and substituted styrenes, the dienes, such as butadiene, Acrylic acid nitrile alkenes, such as ethylene or propylene

and the like. The water-insoluble polymers are free from color-forming nuclei or groups and are preferably also of cyclic nuclei.

In general, vinyl monomers with the least water sensitivity will give the best results and lead to the lowest modulus of elasticity. This is how acrylic acid esters are generally compared the methaeryl esters and polyethylene versus the polymers or copolymers of polyvinylidene chloride is preferred. The vinyl polymers generally have average molecular weights above 10,000.

The particle size of the vinyl dispersion is important because it does not have any for the intended use Light scattering may take place. In general, particle sizes are below the wavelength of light, d. H. below 400 mu, preferred. The particle size can be determined by known methods of emulsion polymerization be controlled, e.g. B. through suitable concentrations of surface-active Mitrein, the type of stirring, the concentration of the reactants, the operating temperature, the rate at which the monomers are added, etc.

In order to fully utilize the advantages of the improved space stability of the emulsions according to the invention, it is advisable to apply the emulsions to a carrier film which is itself a sufficient one Has spatial stability, e.g. B. Polymethylene terephthalates, Polystyrene, polycarbonates, e.g. B. the polycarbonate

7 8

of 2,2-bis-p-hydroxyphenylpropane, polyethylene tere strips 24 hours at constant temperature and phthalate-isophthalate, etc. In general, belong to air-conditioned and with restraint of moisture the polyester films are those that grafted flat onto the Invar plate from highly identical conditions Esters of terephthalic acid with min- placed. Two with Gaertner thread micrometers at least one glycol of the formula 5 microscopes with a total magnification of one hundred times

Tjnrw w rw nw and a smallest micrometer reading of

¹² * 5.08 * 10 ~ ^a cm are arranged in such a way that the Abheriert are in which W a polymethylene radical or stood between the reference marks on the cover an alkyl-substituted polymethylene radical with 0 to layer stripes and the corresponding reference mar-8 carbon atoms, e.g. B. the 2,2-Dimethylpropylen- io ken on the Invar plate with the help of a graduation 1,3-rest, or a cycloalkylene residue with 5 to 6 Koh- provided glass scale can be measured. The lenstoffatomen, z. B. the cyclopentyl-1,4-residue or Invar plate, the microscopes and the cover layer denotes the cyclohexyl-1,4-residue. Mixed polymer strips are all in an air-conditioned housing films, which are up to 20 mole percent, based on the total, accommodated, which is provided with openings for the number of mols of the acids, aliphatic dicarboxylic acids, 15 low-energy and observation windows. z. B. succinic acid, glutaric acid, adipic acid, hexa- By vector addition of these distances and the behydroterephthalic acid and sebacic acid, except for the known distance between the reference marks on terephthalic acid, can also be used. The invar plate will be the distance between the Be-These carriers can have different Bindeniittelschich- traction marks on the strip at a certain th, ζ. B. layers of copolymers of the ao relative humidity determined. The process will have vinylidene chloride, as described in the United States patent with preconditioning for 24 hours, to the document 2,779,684. Distance between the two reference marks on the

The above-described polymers or mixed strips at a different known humidity polymers can have a number, e.g. B. determine one to twelve. The change in length in the two or more, ether groups in the polymer chain, divided by the mean of the values. Such ether groups can be in the form of an ethereal length and divided by the difference in the group-containing glycol derivatives or the percentage relative humidity results in the humidity trend the polymerisation by side reactions has the coefficient of expansion. Invar is one be procreated. The photographic emulsions can be nickel-steel alloy.

nen also on different films, foils and plates 30. The spatial stability is in the form of the sizes Glass, metal, e.g. B. aluminum, on various change in treatment in a similar way water-proof Papers, cellulose derivatives, e.g. B. Cellu- correct. The distance between the fiducial marks loseacetat, cellulose propionate, cellulose butyrate, CeI- is determined on a top layer strip, the Lulose acetate butyrate and cellulose nitrate, films from 24 hours at constant temperature and humidity others Superpolymers, e.g. B. made of polyamides, poly 35 has been air-conditioned. Then the strip vinyl chloride, copolymers of vinyl chloride treated in the usual way and dried in the and vinyl acetate, etc., can be applied. same temperature and humidity as before,

According to a preferred embodiment of the 24 hours air-conditioned and measured to the change-invention The polymer dispersions used are positioned at the distance between the two reference marks to be determined in a manner known per se from a polymerizing 40. The change in size in the treatable liquid monomers produced. This monolung is calculated by adding these changes in length is divided by the average distance using the above-described dispersion, grease emulsified in water and the well-known The stability of the optical density is due to

Emulsion polymerization with the help of a radial density measurements based on the permeability for chain catalyst, e.g. B. a peroxide or 45 diffuse light determined (American Standards Associa- «, A'-azobis-cisobutyronitrile). In dem tion, standard provision Z38.2.5-1946). The measurements Procedure A below will be producing an optical density on both wet and dry particularly preferred dispersion, namely a sol films and films during drying of ethyl polyacrylate explained. Change process at different wet thermometer tempefalls the polymerization can also be carried out in mass 50 temperatures of the drying air, carry out and disperse the dispersions. The values for the impact resistance under different

of the molten polymer in water in counter conditions are angwart with the by R. D. Sp of a dispersant, as described in general and E. B. Cooper in "Journal of Applied Phygemeine happens with polyethylene. sics ", Vol. 28, No. 3, March 1957, pp. 329 to 333,

The following rules of procedure and execution are determined. In this device example, in which the coverings on their moisture tang, the energy absorbed by the film is a coefficient of expansion, measure their spatial structure, if a steel body in motion, their density resistance, their impact resistance, ball penetrates through the film. With the help of a Their adhesiveness and their tendency to curl up can reduce the speed of the photoelectric cell are investigated, the invention is to be further elucidated. 60 Steel ball in free flight at speed tern, but do not limit their scope. after penetrating through the

To determine the moisture expansion the film must be compared.

coefficient becomes a 76.2 cm long strip of the dry adhesive strength of the emulsion to the

Covering with a scribe near each beam is determined by the usual test at End with reference marks, which are close to 65 of the cross-hatched lines through the emulsion cut to the reference marks of a calibrated invar plate and a piece of self-adhesive when the strip and the invar plate come together with a tape on one surface of the emulsion be brought into contact. Then it is pressed and then quickly pulled off. If this

if part of the emulsion is detached from the base, this means poor adhesion. the Wet adhesion strength can be determined in a similar manner after normal photographic processing by measuring the tendency of the wet emulsion to lift off the base when a force acts tangentially at the edge of the cross-hatched lines.

The tendency to curl is measured by determining the weight that is required around a film (25.4 × 30.5 cm) conditioned at 20% relative humidity and 24 ° C to bring flat position.

Procedure A

A fluted reaction vessel with a capacity of 221 is equipped with a thermometer, anchor stirrer and a three-necked attachment equipped, which contains a gas inlet pipe and two reflux condensers. The jar turns 10 to Flushed with nitrogen for 20 minutes and kept under nitrogen overpressure during the polymerization. The vessel is now filled with 101 distilled water, 484 g disodium N- "tallow" -y9-iminodipropionate flakes (96%) and 50 g of gelatin (as a heat stabilizer) are charged with 1040 ml of distilled water. The mixture is held at room temperature for 10 to 15 minutes with moderate stirring and then for 15 to Heated for 20 minutes with stirring in a water bath to 50 to 55 ° C until solution has occurred. The watery one The solution is mixed with 3300 g of ethyl acrylate (from which the polymerization retarder was previously has been extracted with alkali). The reaction mixture is heated to 80 bis with stirring in a water bath Heated to 85 ° C, held in this temperature range for 10 minutes and cooled to 75 ° C. Then it will be 60 ml of 30 percent strength by weight aqueous hydrogen peroxide solution are added to the reaction mixture, and the temperature is kept at 75 ° C until the polymerization begins. After the initial exothermic Reaction has subsided (Note: the reaction can be moderated by adding cold water if necessary, to prevent excessive foam development), 1700 g of ethyl acrylate are added. The bath temperature is set to 75 ± 3 ° C, and there are 19 ml of 30 weight percent aqueous hydrogen peroxide solution added. To

ίο Completion of the second polymerization stage is the Temperature increased to 80 to 85 ° C and held in this range for 2 hours. Then the dispersion heated to 90 ° C, held at this temperature for 10 minutes and one over the course of 1 to 2 hours Subjected to steam distillation to remove residual monomer. The dispersion is on Cooled 50 ° C and filtered through felt to remove any residue. The dispersion thus obtained contains 30 weight percent polyacrylic acid ethyl ester and 2.79 weight percent disodium-N- "Sebum" - /? - iminodipropionate.

Procedure B

A fluted reaction vessel with a capacity of 221 is equipped as described for Method A and described in purged with nitrogen in the same way. The vessel is filled with 8 liters of distilled water and 16.7 g of one High molecular weight polyacrylamides (as a heat stabilizer), which slowly added through a long-handled funnel with a narrow bore and rinsed in with 2.5 l of distilled water will. The mixture is stirred for 2 to 3 hours at room temperature until solution has occurred.

To the solution of the polyacrylamide in the reaction vessel, 667 g of a 30 weight percent aqueous Isopropanol solution of a surfactant of the formula

CH ₃ - C (CHg) ₂ - CH ₂ - C (CH _S ) ₂ (OCH ₂ CH ₂ ) _n OSO ₃ Na

added, which is rinsed in with 400 ml of distilled water. As described for procedure A, a two-stage polymerization is carried out, but instead of the ethyl acrylate Acrylic acid butyl ester is used. The dispersion obtained in this way contains 30 percent by weight of butyl polyacrylate and 1.2 weight percent polyether sulfate surfactant.

Procedure C

Procedure B is essentially repeated, except that 800 g of a 25 weight percent aqueous Solution from “Tamol” 731 (trademark of Rohm &Haas; in Haynes, “Chemical Trade Names and Commercial Synonyms ", 2nd Edition, 1955, Van Nostrand & Co., New York, defined as" sodium salt of a carboxylated polyelectrolyte »), rinsed in with 267 ml of distilled water, in place of the sodium salt of a polyether sulfate can be used as a surfactant. As for that Method A described is a two-stage polymerization carried out, but with methyl methacrylate instead of ethyl methacrylate is used. The dispersion obtained in this way contains 30 percent by weight of methyl polymethacrylate and 1.2 percent by weight of the sodium salt of the carboxylated polyelectrolyte.

Method D

Procedure A is essentially repeated, but with 716 g of a 28% strength by weight aqueous solution of a surface-active agent formula

tertCJEL

(OCH ₂ CH ₂ ) ₂ SO ₃ Na

rinsed in with 714 ml of distilled water instead of disodium N- "tallow" - _/ e-iminodipropionate. Instead of the ethyl acrylate, a monomer mixture of 3500 g vinylidene chloride and 1500 g 2-ethylhexyl acrylate is used in this case.

An aqueous solution of 33.3 g of ammonium persulfate in 100 ml of distilled water and an aqueous one A solution of 16.7 g of sodium metabisulphite in 50 ml of water is used in place of the hydrogen peroxide. The polymerization is not carried out at 75 ° C, but at 25 to 30 ° C. The thus obtained The dispersion contains 21 percent by weight of polyvinylidene chloride and 9 percent by weight of 2-ethylhexyl acrylate in the form of a copolymer as well as

309 750/322

1.2 percent by weight of the sodium salt of the alkylaryl polyether sulfonate as a surfactant.

example 1

A high-contrast silver iodide-silver bromide emulsion is produced in a known manner by mixing solutions of silver nitrate, ammonium bromide and potassium iodide using 14.7 g of gelatin as protective colloid per mole of silver halide. The emulsion is divided into two parts A and B and freed from undesired soluble salts by known photographic washing processes. Each of the two emulsions is digested in the presence of the usual chemical sensitizers and carbocyanine dyes to impart panchromatic sensitivity. After digestion, a further 191 g of gelatin per mole of silver halide are added to emulsion A, but only 126 g of gelatin per mole of silver halide to emulsion B and a combination of 40 g of dextran (average molecular weight about 75,000) and 223 g of that according to method A. 30% strength polyacrylic acid ethyl ester dispersion produced was added. The additives usually added after digestion (anti-fogging agent, wetting agent, halide, etc.) are added to both emulsions. Each emulsion is coated in a silver halide layer thickness of 63 mg silver per square decimeter on a 0.1778 mm thick, biaxially oriented polyethylene terephthalate film according to Example 4 of U.S. Patent 2,779,684. Each film is coated on the back with a layer containing common antihalation dyes. The binding agent for the layer on the rear side is applied in a layer ^{thickness of 90 mg / dm 2} and consists of gelatine for film A, 1 part of gelatine for film B and 2 parts of dispersed ethyl polyacrylate. A third FiImC is a commercially available film containing only gelatin as a binder with similar properties to the FiImA and serves as a second control sample.

ίο The exposure of all three films takes place in one normal sensitometer with a 1/2 step wedge. the Films are then processed in the usual p-monomethylaminophenol sulfate hydroquinone developer developed, fixed in a hardening fixing bath containing sodium thiosulfate, and washed. The through transmission Optical densities measured by diffuse light (American Standards Association, Normvorschrift Z 38.2.5-1946) are determined on the wet film, and the measurement is made on the

ao dry film repeated. In order to obtain typical measured values, the determinations carried out on four duplicate samples for each film and the results as the mean values of the measured values Values given. These are then calculated as a function of the wet nominal temperature of the drying air, d. H. the film temperature during drying, evaluated when the temperature is in steps of 5.6 ° C increases from 21.1 to 37.8 ° C. The changes in optical density, expressed as a percentage of optical Wet densities are given in Table I for the three fumes.

Table I.
Percentage change in optical density on drying

FiImA

FiImB

FiImC

Wet thermometer temperature

21.1 ° C

26.7 ° C

32.2 ° C

37.8 ° C

Area of density changes

Moisture expansion coefficient, cm / cm / ° / o relative Humidity at 70 ° C

-7.5% + 2.5% -7.3Vo + 2.6% + 8.3% + 1.8% + 16.0% + 2.6% 23.5% 0.8%

2.4 x 10-5

1.4 · ΙΟ " ⁵

-11.1%

-11.9%

-12.2%

+ 2.4%

14.6%

2.0 x 10-5

The values show the small (and almost constant) changes in the optical density of film B, which contains the binder modified according to the invention, in contrast to the known films A and C, which only contain gelatine as a binding agent. In the latter, one occurs at a critical temperature sudden change from - to + one, which is characteristic of films with gelatin binders of known types is. In addition to these improvements in optical density stability, Table IV shows that the Moisture expansion coefficient of film B (the dextran and a polyacrylic acid ethyl ester dispersion contains) between 30 and 80% relative humidity at 70 ° C is much lower than the corresponding Coefficients of films A and C containing only gelatin as a binder. Film B also shows a better adhesion of the emulsion to the base, a lower tendency to curl and a faster drying speed than films A or C.

Example 2

Example 1 is used; in this case, however, the precipitation of silver halide becomes more well known Way carried out in such a way that a low-contrast emulsion is formed. As in example 1 will divided the emulsion into two parts D and E. Part D is only mixed with gelatin, while Part E a polyacrylic acid ethyl ester dispersion and dextran can be added. With these emulsions the Films D and E coated.

The evaluation of these fumes according to Example 1 shows that the stability of the optical density in the transition from wet to dry state is much greater for film E than for control film D. Also, film E outperforms film D in terms of volume stability, impact resistance and drying speed.

Example 3

The films of Example 1 are subjected to further tests. Each film is exposed and further processed, and the optical densities are in the manner described above in the wet state for determined each film near 1.0 and 2.0. Then every film becomes one left to dry air-conditioned room under the following conditions.

Wet thermometer temperature 13.9 ° C

Dry thermometer temperature .. 21.7 ° C Relative humidity 40%

The changes in optical density are recorded every 2 minutes. The film is considered dry if there is no further change in optical density. Then everyone will Film rewetted and density measurements repeated during the second drying. The results are shown in Table II. It can be seen that FiImB has much smaller fluctuations in optical Density at transition from wet to dry state is shown as film A, both during the first drying as well as after re-moistening during the second drying. aside from that Film B dries much faster than film A.

Table II

First drying

Wet density

maximum density

Dry density drying time
Minutes

Second drying

Wet density

Dry density

Drying time minutes

Optical density
at about 1.0

FiImA

Movie B

Optical density
at around 2.0

FiImA

FiImB

1.25 1.19

2.23 2.00

1.30 1.20

2.32 2.05

1.18 1.17

2.14 2.02

1.08
1.14

1.94
1.94

1.16
1.13

2.08
1.96

22nd
10

20th
12th

Example 4 sion divided into 4 parts. Dextran (medium molecular one blue-sensitive silver iodide-silver bromide weight 75,000) and an emulsion according to method A. is made in a known manner by mixing dispersion of ethyl polyacrylate wervon Solutions of silver nitrate and ammonium brodine in the amounts given in Table III and potassium iodide in the presence of 14.6 g of gel, and films according to Example 1 are betine produced per mole of silver halide. After layering, the following results are obtained Wash out the unwanted soluble salts after. The contrast values and the relative sensitivity U.S. Patent 2,772,165 method and sensitivities are derived from the usual curves for digestion in the presence of a total of 40 the optical density as a function of the logarith-133 The emulsion of the exposure time is obtained by g of gelatin per mole of silver halide.

Table m

Movie

Amount of binder per mole of AgX

Gelatin, g

Dextran, g

Polyacrylic acid ethyl ester *, g

Relative sensitivity

contrast

Change in optical density during drying **

at the density value 1.0

at the density value 2.0

133 0 0

1.00 1.97

-0.06 -0.14 133
40
67
1.32
1.97

+ 0.01
+0.04

133
40

100
1.42
1.93

-0.03
+0.04

133

20th

67
1.23
1.95

0
-0.05

* Calculated as the amount by weight of the pure compound in a 30% dispersion. ** Values measured at a wet thermometer temperature of 32.2 ° C.

The same four films are treated as in Example 1 and at four different wet thermometer temperatures dried, keeping the relative humidity constant.

This example shows the interaction of the dextran and the dispersed polymer the stabilization of the optical density. It is to be noted that the films G, H and I have a smaller one

65 Show sensitivity to changes in drying conditions between 32 and 38 ° C. The dextran It seems that the position of the curve is mainly influenced by the position of the curve, while the dispersed polymer appears to influence its shape. By interpolating, you get an amount of dextran and polymer dispersion that is convenient to keep the optical density constant during the transition from the wet to the dry state

a density value of 2.0 across the entire drying range.

Example 5

Films A and B of Example 1 are conditioned at different relative humidities, and the moisture expansion coefficient will be

determined for each area according to the method described above by changing the location of two fiducial marks on the ends of a film strip (1.9 x 25.4 cm) relative to the marks on one Invar rod measured using two microscopes equipped with thread micrometers will. The results are given in Table IV.

Table IV Coefficient of moisture expansion, cm / cm / ° / o RF *

30 to 50% RH 50 to 65% RH 65 to 80 Ve RF Average
30 to 80% RH area FiImA
Movie B 1.62
1.73 4.24
2.60 1.42
1.25 2.43
1.86 2.82
1.35

* RF = relative humidity.

These results show that the coefficient of moisture expansion of film B is much less sensitive to changes in humidity than that of film A. In addition, this has Coefficient for film B has a lower mean value for the relative humidity range from 30 to 80% than the state of the art film A.

Example 6

A panchromatically sensitized silver iodide-silver bromide emulsion is prepared similarly to Example 1, the silver halide being based on known Way is precipitated in such a way that an emulsion of medium contrast strength is formed. After this After digestion, enough gelatin is added to the emulsion that the total concentration of gelatin increases 133 g per mole of silver halide is brought. Having part of the emulsion for comparison as only Gelatin-containing control emulsion is removed, the remainder of the emulsion is 223 g a 30 weight percent colloidal dispersion of polyacrylic acid ethyl ester (manufactured according to method A) added per mole of silver halide, which is 67 g of pure ethyl polyacrylate per mole of silver halide is equivalent to. Then the emulsion is divided into a number of parts and each part becomes one the polysaccharides given in Table V added. The emulsions are made according to Example 1 applied to films.

Table V

Polysaccharide

Amount of binder per mole of AgX polyacrylic acid ethyl ester

gelatin

Polysaccharide

Relative
sensitivity

contrast

modification Curl up the optical density at the D. Dry* A. -0.11 C. 0 B. + 0.06 C. -0.09 - -0.02 - -0.20 C. -0.15 - -0.01 - +0.07 - -0.01 -0.03

Shock resistance

None (control sample)

Dextran

Dextran

Dextrin

Dextrin

Araban

Araban

Galactan

Galactan

Mannan,

Mannan

133
133
133
133
133
133
133
133
133
133
133

* With an optical density of

40 67 40 67 40 67 40 67 40 67

0 67 67 67 67 67 67 67 67 67 67 1.0

1.3
1.6
1.7
1.7
1.9
2.0
1.7
1.3
1.5
1.7

1.4
1.5
1.7
1.9
1.7
1.9
2.0
2.2
1.4
1.4
1.8

C A B B

C C

2.0.

The values in the table above are obtained by evaluating the films according to Example 4. the Curling tendency and impact resistance are determined as described above. You can see that modified binders increase sensitivity and contrast, improve stability the optical density on drying, a reduced tendency to curl and a better one Impact resistance. It should also be noted that between the various polysaccharides a Difference in the concentration required for the highest stability of the optical density

stands. In the case of araban, the stability of the optical density is improved with increasing concentration, and the results show that even higher concentrations would be required to cope with Araban to achieve the same stability of optical density as achieved with better polysaccharides will.

Example 7

One works according to Example 6 up to and including the process stage of the addition of gelatin up to one Concentration of 133 g per mole of silver halide and

taking part of the emulsion as a control sample, which contains only gelatin as a binder. The remainder of the emulsion is divided into a number of parts, and each part becomes different Amounts of dextran and colloidally dispersed polyacrylic acid ethyl ester (SO weight percent dispersion, prepared according to method A) according to Table VI added. The emulsions are applied and evaluated according to the previous examples. Man sees that all emulsions with modified binders have a greater sensitivity and a have better optical density stability than the control sample. Emulsion # 4 shows the best Overall combination of properties.

Tabel Amount of binder per mole of AgX Dextran Polyacrylic acid
ethyl ester 100 VI modification
the optical density
while drying * Shock resistance gelatin G G 67 Dynes / cm ² No. G O 0 Relative
sensitivity -0.11 53 133 13! 93 -0.04 82 1 133 27 80 1.0 -0.09 70 2 133 40 67 1.1 0 69 3 133 53 53 1.3 +0.02 58 4th 133 40 1.3 -0.03 57 5 133 67 1.5 + 0.06 58 6th 133 1.5 7th 1.5

* Measured at an optical density of 2.0.

Example 8

One works according to Example 6 up to and including the process steps of adding gelatin up to to a concentration of 133 g per mole of silver halide and the removal of part of the emulsion as a control sample for an emulsion containing only gelatin as a binder. To the rest of the emulsion 40 g of dextran are added per mole of silver halide, whereupon this remainder is divided into 4 parts. to Each of the four parts will be 223 g of a 30 weight percent colloidal dispersion per mole of silver halide one of the polymers prepared by processes A, B, C or D was added. This addition corresponds to an amount of 67 g of the pure polymer per mole of silver halide. Then the emulsions applied and evaluated according to Example 6 with the following results.

Table VII

Dispersed polymer

Dispersants

gelatin

Amount of binder
per mole of AgX
Polymer

Dextran
G

Relative
sensitivity

modification

the optical

density

at the

Dry*

Impact resistance dynes / cm ²

None None 133 0 0 1.0 -0.11

Polyacrylic acid ethyl ester iminodipropionate 133 67 40 1.4 0

Butyl polyacrylate, polyether sulfate 133 67 40 1.0-0.05

Polymethacrylic acid methyl polycarboxylate 133 67 40 0.7-0.05

ester
Copolymer of vinyl polyether sulfonate 133 67 40 1.2-0.05

idene chloride and acrylic

ethylhexyl acid ester

* Measured at an optical density of 2.0.

The dextran used in this example and in example 7 is the same as in example 1.

0.53 0.65 0.60 0.23

0.22

From the table above it can be seen that all modified binders are a substantial improvement the stability of the optical density during the transition from the wet to the dry state. The best combination of properties is found in the emulsion, in which ethyl polyacrylate dispersed with the amphoteric dispersant disodium-N- "tallow" ~ / minodipropionate is. By further exchanging the polymers and the dispersants, you can get different ones desired combinations of properties.

The films can have various interlayers in order to attach the emulsion layer to the support as is customary in the manufacture of photographic films and plates. as well they can have various auxiliary layers, such as anti-abrasion layers and backing layers or Anti-halation sub-layers included.

The emulsions can be made by adding emulsion sensitizers be modified, e.g. B. by adding alkyl thiourea, phenyl isothiocyanate, Sodium thiosulfate, alkyl isothiocyanate, metal compounds, e.g. B. gold, platinum, palladium, iridium, rhodium, Mercury, cadmium, etc., anti-haze agents, e.g. B. 2-mercaptotetrazole, benzotriazole, Triazindes, tetrazindes and 5-nitrobenzimidazole, sensitizing dyes, color formers, the in

309 750/322

U.S. Patents 2,400,532, 2,423,549 and 1925,508, polyoxyalkylene ethers, polyglycols and amines, hardeners, e.g. B. formaldehyde and other aliphatic aldehydes, dimethylolurstoffr, Trimethylamine, chrome alum and other chrome compounds, coating aids, Image color modifiers, lightening agents, Colorants, e.g. B. Pigments, matting agents and other emusion auxiliaries.

The photographic requirements for emulsions, which are intended for graphics are generally best served by silver halides, where the predominant halide is the bromide. To change the photographic behavior, are up to 10 mole percent iodide and the usual chemical sensitizers and optical sensitizing dyes added. The particular advantages of the binder combination according to the invention, such as the stability of the optical density during the transition from the wet to the dry state, the shock resistance ao speed, dimensional stability, adhesion to the substrate, evenness and drying speed, will also be used in various degrees with other halides within a wide range of compositions achieved, e.g. B. with silver chloride, silver chloride bromide and silver iodide-chloride-bromide emulsions.

Although the films of the invention show their greatest value for use in graphics many of the extraordinary properties are also found in other photographic films beneficial, e.g. B. cinematographic films, X-ray films, portrait films and color films. the Binders can be used with single-layer or multi-layer coated products. In general these materials can also be used for special processing changes as they are in the well-known films such. B. for the production of dye inhibition films or for Production of pianographic printing plates, wash-off relief films and release films such as for silk screen printing and engraving are common.

The invention provides particularly useful photographic emulsions for the manufacture of fins available that have improved physical properties and improved optical stability Density of the developed image in transition from the wet to the dry state. the Films produced according to the invention do not have the disadvantage that the optical density of the developed Image decreases as the film dries. Of the improved physical properties is that., Stability of space is particularly important; however, the improved flexibility and the improved are also important Adhesion to the base. These advantages are provided without sacrificing sensitometric or other physical properties of the varnish achieved. So, as can be seen from the examples, significantly increases photographic sensitivity. The preferred ones used in the present invention Classes of ionic dispersants enable the formation of sufficient polymer particles small size to get a see-through after mixing with gelatin, coating and drying To produce film.

The amphoteric dispersants which are particularly preferred for panchromatic emulsions impair in contrast to the previously used anionic and cationic surfactants » dye sensitization does not. Another advantage is the simplicity of the invention Procedure. Since all additions are made in the form of aqueous solutions or dispersions, the process can can be carried out in a simple and economical manner on an industrial scale without a special system, e.g. B. to recover the solvent is required.

Polymers are often incompatible with one another, and this results in the case of mixtures from two or three polymers difficulties when, as in the case of photographic films, on the Clarity matters. In polymer technology, no reliable rules are known according to which It would be possible to predict in which cases polymers are compatible with one another and which combination of properties the finished polymer mixture has. In the to be used according to the invention The three different polymers are compatible with each other and provide a binder mixture photographic emulsions of excellent optical clarity and other useful photographic and physical properties. In the case of the emulsions according to the invention, im corresponds to generally the sum of the combination of the three polymeric binder components in the absence light absorbed and scattered by silver and silver salts with an optical density of no more than 0.1, which is an advantage.

Claims (12)

PATENT CLAIMS: 1. Photographic gelatin silver halide emulsion, characterized in that it consists of 1. an aqueous phase, which is used as constituents a) 20 to 85 parts by weight of gelatin and b) 2.5 to 40 parts by weight of a water-soluble polysaccharide of the empirical formula (C ₆ H ₁₀ O ₅ ) ,, or (C ₅ H ₈ O ₄ ), contains, wherein the monomer units naturally occurring AMose or Are ketosis units and the number η has a value from 20 to 600, and 2. 10 to 70 parts by weight of a non-aqueous dispersed in the aqueous phase Phase of water-dispersible colloidal particles from a practically water-insoluble one Addition polymers of an ethylenically unsaturated monomer with a molecular weight of less than 250. 2. Emulsion according to claim 1, characterized in that the particles of the addition polymer an average diameter of less than 400 μm and an average molecular weight of more than 10,000. 3. Emulsion according to claim 1, characterized in that the addition polymer is an alkyl polyacrylate in which the alkyl group contains 1 to 8 carbon atoms. 4. Emulsion according to claim 1, characterized in that the addition polymer is a polyacrylic acid ethyl ester is. 5. Emulsion according to claim 1, characterized in that the polysaccharide is dextran. 6. Emulsion according to claim 1, characterized in that it contains at least one amphoteric Dispersant of the formula RNH _7n (CH ₂ CH ₂ COOM) ,, contains, in which R is an alkyl group with 12 to 18 carbon atoms, m is 0 or 1, ρ is 2 - m and M is a hydrogen, sodium, potassium or ammonium ion. 7. Photographic material, characterized in that it consists of one with at least one Photographic emulsion layer according to claim 1 coated support. 8. Material according to claim 7, characterized in that the particles of the addition polymer in the emulsion a mean diameter of less than 400 ηΐμ and a mean one Have a molecular weight of at least 10,000. 9. Material according to spoke 7, characterized in that the addition polymer in the emulsion sion is an alkyl polyacrylate in which the alkyl group contains 1 to 8 carbon atoms. 10. Material according spoke 7, characterized in that the addition polymer in the emulsion is an ethyl polyacrylate. 11. Material according to spoke 7, characterized in that that the polysaccharide in the emulsion is dextran. 12. Material according to claim 7, characterized in that the emulsion is at least one amphoteric dispersant of the formula RNH _n J (CH ₂ CH ₂ COOM) ,, contains, in which R is an alkyl group with 12 to 18 carbon atoms, m is O or 1, ρ is 2— m and M is a hydrogen, sodium, potassium or ammonium ion. ao Considered publications: German publications No. 1121 468, 076;
U.S. Patent Nos. 2,835,582, 2,811,494, 848 434, 2,768 080. © 309 750/322 11.63